The Thunderbolt mod gives arrows from the Paris, Dread, Paris Prime, Attica, or Cernos a 7.5% chance per rank of exploding on impact for a maximum of 30% chance at rank 3, dealing 250 Blast damage to the target, as well as to nearby enemies within 10 meters of the blast (scaled by distance).

Pair with a high-rank Multishot mod for maximum effect. Calculating per shot, you'll have a 48.9 % chance of at least one explosion at max rank for both Split Chamber and Thunderbolt. The chance for two explosions is 8.1 %

When facing groups of enemies at medium to long range, maximize splash damage by aiming for a nearby wall or floor surface rather than directly at an enemy.

Since explosive damage is unaffected by the amount of time you've charged the shot, rapid snap shots can be very effective at quickly taking out large groups of enemies.

Currently, the mod has no effect on bows' stealth properties; killing an unaware enemy with an explosive arrow will not trigger an alarm. However, missing a shot will still be noticed by enemies, be it explosive or not.

This mod pairs well with the Attica due to the latter's high volume of fire compared to other bow-type weapons, ensuring a very high chance of bolts exploding within a short period of time. Combined with the higher ammo capacity, using Thunderbolt on this weapon is very effective.

However, Thunderbolt's damage doesn't scale, can't be improved and only gives a very low average dps (damage per shot) boost of 75 (single target) while elemental damage mods will boost your weapon damage for 60% at the cost of 9 calibration points. It is recommended to not use this mod against enemies above level 20.

The explosion will hurt (or even kill) the player if he stays in the blast radius, as well as knocking him down, if the Blast element procs.

Blast radius is exactly 10 meters (so far not expandable by mods).

Possible bug: If an enemy is hit with an exploding arrow directly, the blast does not seem to affect other nearby enemies.

Since Update 7.11, the explosive damage is not affected by base damage and elemental mods.

As of Update 8, the mod was changed from being exclusive to the Paris. It now works on the other bow-type weapons including the Dread, Cernos and Attica.

As of Update 9.5, the mod drops more commonly from normal mobs than before due to drop table changes.

Prior to Update 9.8, the base damage of Thunderbolt was fixed at 250. This meant mods such as Serration did not increase its damage. Additionally, when it procced, it would replace the arrow's damage. This resulted in lower single target damage than if the arrow did not proc Thunderbolt's effect and dealt 'normal' damage. However, Update 9.8 fixed 'Thunderbolt's explosive damage from trumping impact damage'. Now 'projectile damage is applied first, then chance to explode is checked.'